WO2023194455A1 - Method for producing heat and cold in a flexible and elastic material and alternative devices for implementing this method - Google Patents

Abstract

Method involving a flexible heat pump actuated by recuperated environmental energy and associated device. The method that forms the subject of the invention is a method for producing heat and cold in a flexible material comprising gas-filled fluid-tight cells by compressing and expanding the gas trapped in these cells when pressure is applied to the flexible material such as, for example, when the foot of an individual or of an animal is pressing down on the ground, or a tyre is in contact with the road. The flexible material is preferably silicone or some other elastic or hyperelastic elastomer and is made up of three layers: * a layer provided with so-called cold cells and of which the geometry or hardness allows these to be compressed before the so-called hot cells, * a layer provided with so-called hot cells and of which the geometry or hardness allows these not to be compressed while the so-called cold cell is being compressed, * an intermediate layer between the previous 2 layers and comprising nozzles of a geometry suited to proper expansion of the gas. These three layers are superposed and assembled in a fluid-tight manner so that each so-called cold cell is in communication with a so-called hot cell via one of the nozzles. The method may be employed in the soles of shoes so as to maintain a cool temperature when the individual is running on baking-hot ground or a warm temperature on freezing ground since these soles are thus reversible. With each footstep, the foot will compress the so-called cold cells and all of the gas will be compressed into the so-called hot cells via the nozzles. As it is compressed, the gas will naturally warm up in accordance with the laws of thermodynamics. When the foot leaves the ground and there is therefore no longer any compression, the flexible material will regain its volume through the elasticity of the material, and the so-called cold cells will draw the gas from the so-called hot cells and therefore expand it via the nozzles and this will naturally cool this gas in accordance with those same laws. The cycle is ongoing as long as the individual is walking or running.

Description

Description

METHOD FOR PRODUCING HEAT AND COOLNESS IN A FLEXIBLE AND ELASTIC MATERIAL AND ALTERNATIVE DEVICES FOR IMPLEMENTING THE Associated METHOD

The present invention relates to a method for producing heat and coolness in a flexible material comprising sealed cells filled with gas, by compression and expansion of the gas trapped in its cells and its associated device.

[0002] The preferred application being shoe soles to maintain a cool foot temperature even when walking on a very hot road or a warm temperature on frozen ground.

Prior art

[0003] If there are devices for warming the feet such as for example insoles or socks with electrical resistance powered by batteries or exothermic chemicals, none of these systems makes it possible to maintain a heat supply for a period of time. sufficient for a good number of activities such as for example, for 8 hours or more for workers in cold stores, extreme trailers, the military, etc.

[0004] On the other hand, there are few devices for refreshing shoe soles. There are many devices of insoles filled with a gel which are placed beforehand in a freezer in order to store cold but this type of device is impractical because on the one hand the cold is intense at the start, at the risk of create burns, then quickly becomes less effective and on the other hand, the duration of maintaining the cold is very short (a few minutes to tens of minutes) and therefore not suitable for working days or one-hour jogging sessions or more.

[0005] There are many devices which claim the use of Peltier effect components as in patent applications KR20160066190, US2012018418 or W02005087031. But these devices require a significant power supply because the efficiencies of Peltier effect components are not very good. Thus, the provision of refrigeration will not be possible for periods of more than one hour due to rapid battery depletion. In addition, these Peltier effect components are generally made of ceramic and are therefore very fragile. Finally, between the weight of the components and the batteries, it quickly becomes too heavy in sports shoes which generally benefit from being light.

[0006] There are also devices which use breathable materials to evacuate water, as described in patent US2018220739 or porous materials for better ventilation as in patent CN107788617 but none of these systems allows real thermal regulation and a strong lowering or raising of temperature.

[0007] There are also processes for ventilating a material (in this case a shoe) from the outside air, as described in application FR2958505A1, but this is absolutely not a cooling process. or heating: it is only a process of ventilation of a material from the outside air. So, if the outside air is very hot like in summer in India (51°C) for example, it will be air at 51°C which will enter the shoe! We are far from thermoregulation. Indeed, application FR2958505A1 describes and claims a shoe, certainly with a pocket (large cell) but this is in communication with the exterior and interior of the shoe and therefore absolutely not waterproof (communication with the exterior is also claimed there). This is supported by the fact also that it is never described or claimed that the air is put under pressure as in our present application to implement the principles of thermodynamics and in particular the heating of the air thanks to its putting under pressure.

[0008] In application FR1501793A it is also not possible to compress and decompress the air in the cells. On the contrary, there is described and claimed a sole equipped with means of ventilation because the cells, as specified several times, are open and could absolutely not keep the air pressure due to the weight of the person. In addition, it is specified that these cells contain a powder to be dispersed on the feet and therefore that the non-watertight nature is fundamental.

[0009] Thus, in applications FR2958505A1 and FR1501793A, it would be impossible to heat or cool independently of the outside air because there is described a process for ventilating a material from the outside air and therefore, if the The outside air is very hot as it is currently in India (51°C), it will be air at 51°C which will enter the shoe! and it would be impossible to cool the foot with such hot air. Likewise, if the outside air is very cold like in winter (-30°C in the mountains, in Canada...), it will be air at -30°C which will enter the shoe! and it would be impossible to warm the foot with such cold air.

[0010] Only a process which uses the principles of thermodynamics as we claim in our present application can actually produce calories and frigories and is capable of providing real freshness in heat waves or heat in cold weather for a long time. duration (as long as you walk or run).

[0011] Application FR 1871095 does mention a thermodynamic process but its implementation was difficult because the cells were hollow in the material making compression difficult and numerous other innovations, as will be described, had to be made for it. make it more efficient. This request concerns therefore an improvement patent dependent on application FR 1871095.

Description of the invention:

[0012] The method which is the subject of the invention relates to a method for producing heat and freshness in a flexible material, comprising sealed cells filled with gas, by compression and expansion of the gas trapped in its cells when pressure is exerted. mechanical on said flexible material such as for example when pressing the foot of a person or an animal on the ground.

[0013] The flexible material is preferably made of silicone or other elastic or hyperelastic elastomer such as natural rubbers, butyl rubbers, etc. and is made up of three layers:

* a layer provided with so-called cold cells and whose geometry or hardness allows mechanical compression greater than that of so-called hot cells,

* a layer provided with so-called hot cells and whose geometry or hardness allows it to be not or only slightly compressed during mechanical compression of the so-called cold cell,

* an intermediate layer between the 2 previous layers comprising nozzles with a geometry adapted to good gas expansion.

The 3 layers being assembled in a sealed manner so that each so-called cold cell is in communication with a so-called hot cell via one of the nozzles and all the cells are filled with the surrounding gas during assembly.

[0015] The mechanical compression of the flexible material thus causes the compression and therefore heating of the gas from the cells of the cold layer towards the cells of the hot layer via the nozzles.

[0016] During mechanical decompression, thanks to the elasticity of said material, the same gas expands and therefore cools via said nozzles towards the cells of the cold layer.

[0017] In order to optimize the gas expansion phase during mechanical decompression, the nozzles can have a convergent or divergent shape, with a rounded, elliptical shape or for example the Laval nozzles.

[0018] [Fig.l] shows a cell before assembly with the hot layer (1), compressed air reception zone, the cold layer (2), air relaxation zone after compression, and the layer intermediate (3), containing the nozzles (4).

These three layers are superimposed so that each so-called cold cell is in communication with a so-called hot cell via one of the nozzles as shown in [Fig.2].

The three layers can be assembled, to be airtight, at atmospheric pressure or under pressure so that the cells are filled with gas under pressure or not.

[0020] Sealing is a very important characteristic. Indeed, if we use a material having a permeability to gases, such as air, greater than 20 Barrer, the compression/expansion cycles will cause a slow but progressive air leak, leading to permanent crushing of the cells thus limiting thermodynamic operation. The production of heat and cold will then only be effective for 1 to 2 hours. To ensure thermodynamic production for 8 hours for example (one working day), a permeability of less than 4 Barrer is sufficient and for operation greater than 40 hours (for extreme trails for example) a permeability of less than 1 Barrer will be necessary.

[0021] So that the so-called hot cells cannot be or be slightly compressed during the mechanical compression of the so-called cold cell, this can be achieved either with a particular geometry such as preferably the addition of reinforcements inside the alveoli or an increase in the thickness of the walls of the alveoli or with a hardness greater than that of the so-called cold alveoli.

[0022] In the case where the so-called hot cells have a hardness which allows them not to be compressed or only slightly during the mechanical compression of the so-called cold cell, this hardness will be greater by at least 10 Shore A, than that of the latter.

[0023] The flexible material can thus be used as a sole in shoes in order to maintain a cool temperature when the person runs on hot ground, for example. During each step, the foot will compress the so-called cold cells and the gas from these cells will be pushed via the nozzles towards the so-called hot cells which will therefore act as adiabatic enclosures whose gas when compressed will heat up.

[0024] When the foot leaves the ground and therefore there is no longer any mechanical compression, the flexible material will regain its volume through the elasticity of the material and suck the gas through the nozzles which will relax the gas and therefore cool it.

The hardness values used for the so-called cold cells are 10 to 30 Shore A and 20 to 50 Shore for the so-called hot cells. Note that if the 2 layers had the same hardness, the gas compressed by the pressure of the foot would be distributed equally between the incompletely compressed cells of the 2 layers, heating would be uniformly distributed and therefore during expansion, thermodynamics teaches us that the temperature would return to its initial value and therefore we would not be able to obtain a hot side and a cold side.

[0026] Thus it is thanks to a differentiation in the compressibility of the two types of cells, either with a difference in hardness of the two layers, or by a difference in shape, that the so-called cold cells are deformed by the pressure of the foot so that all the compressed gas goes into the so-called hot cells which practically do not deform. The compressed gas is therefore heated naturally by the laws of thermodynamics, and is found entirely in the so-called hot cells which are found thus at a higher temperature than the so-called cold cells.

Elastomers such as silicone, for example, do not have significant conductivity. Thus, the alveoli may not sufficiently transmit heat or cold to the feet and the alveoli will function more like an adiabatic enclosure without exchange with the outside. It is therefore preferable to increase the thermal conductivity in the hot and cold layers by adding a powdered metal (copper for example) or diamond powder in the elastomer but not in the intermediate part containing the nozzles in order to to ensure thermal insulation and to properly separate heat flows.

[0028] [Fig.2] to [Fig.5] show in sections the device intended for example to be arranged like a sole in shoes with so-called cold cells in contact with the foot. Example of operation with air:

[0029] [Fig.2], the flexible cellular material is at rest and the gas is uniformly distributed in the cells at temperature Ta and pressure Pa. We distinguish the two types of cells and the nozzle.

[0030] [Fig.3], a pressure, such as for example the support of a foot represented by an arrow (5), on the ground (6), is exerted on the flexible material and as the so-called cold cells are more compressible than the so-called hot ones, all the air (7) goes into the latter.

[0031] [Fig.4], the gas will then be compressed to the pressure Pi (depending on the pressure exerted, i.e. approximately 2 bars for equi-volumic cells) and will therefore heat up to the temperature Ti following the laws of thermodynamics. The temperature Ti of the gas will therefore be equal to: [Math.l]

Ta x (Pi/Pa) ^(v ' ^1)/v where Y is the adiabatic constant of the gas (1.4 for air at 293°K), or 376°K if Ta is 293°K. The heat from the gas will then dissipate in the material towards the foot or the ground (or shoe).

[0032] [Fig.5] shows the material as the pressure is released (when the foot leaves the ground). The elasticity of the material causes the cells to regain their shape, a force represented by an arrow (8). The gas under pressure, at the temperature Tf, will leave the so-called hot cells to relax in the so-called cold cells via the nozzles and thus cool down to reach the temperature Te: [Math.2]

Tf x(Pa/Pi)(y-l)/Y is 285°K, i.e. a temperature 8°K lower than the initial temperature Ta.

[0033] It is really a thermodynamic process for producing cold and heat in a sole which is claimed to mirror what happens in an air conditioner using the Carnot cycle (compression/expansion) in the so-called hot cells. (compression zone), the so-called cold cells (relaxation zone)) and a compressor (the foot). The innovative character resides in the fact that this cycle is made of a flexible material capable of being compressed and returning to its initial shape thanks to its elasticity.

According to another arrangement, the flexible material can be used as a heating means. To do this, simply invert the sole and therefore ensure that the so-called hot cells are in contact with the foot. Thus, the heat generated during compression will be in contact with the foot while the cold layer will be in contact with the bottom of the shoe.

[0035] The flexible, elastic or hyperelastic (and therefore highly deformable) nature of the material is fundamental so that the weight of a person can deform said flexible material but also so that after releasing the pressure, the material recovers as quickly as possible. its initial form.

[0036] The cells can therefore be sized according to the weight of the people and the size of the shoe so that the pressure is sufficient to properly compress the so-called cold cells.

[0037] Preferably, the cells must be in relief so that there is as little material as possible all around (hollow cells in the material are much more difficult to compress with a foot).

[0038] The ratio of the volumes of the so-called cold and hot cells is also important. Indeed, if they have the same volume, during complete mechanical compression of the cold cell all the gas in the hot cell will be at a pressure of 2 bars which corresponds to a rise in air temperature of 83 °C approximately.

[0039] On the other hand, if the so-called cold cell has a volume double that of the hot cell, the pressure obtained during compression will be 3 bars and the rise in air temperature will be 120°C. approximately which will allow better heating of the foot.

The gas contained in the cells can simply be air, but it is advantageous to take gases having a higher adiabatic constant y such as a monatomic gas (Argon for example) or polyatomic gas (CO2 for example). with the addition possibly of a humidity greater than 20% (to use the latent heat of vaporization of the water) in order to obtain a higher yield.

[0041] According to another of the preferred arrangements, the material and the shape of the cells can be adapted to the morphology of domestic animals such as cats and dogs who often burn their pads when they move on a road in direct sunlight. This is particularly the case for rescue dogs.

[0042] According to another arrangement, the flexible cellular material can be used as a carpet in establishments open to the public or businesses with a lot of traffic so that the numerous pressures of the feet provide thermoregulation.

[0043] According to another arrangement, the flexible cellular material can be used in tires to allow continuous cooling. This is all the more interesting since electric cars replacing thermal cars are heavier and more torquey and therefore subject to easier tire heating.

[0044] In this case, the cells of the hot layer will advantageously be grouped together to form the actual chamber of the tire and the cells of the cold layer will be arranged on the periphery of the tire where they will undergo compression and relaxation cycles when the car is moving. On the other hand, in this case, it is preferable that the cells are hollow because the pressure exerted by the car is much greater than that of a foot.

[0045] According to another arrangement, the flexible cellular material can be used in peristaltic pumps. To do this, it is enough to arrange the cells around the pipe made of elastic material which ensures transport and thus cool or heat the fluid thus pumped.

Claims

Claims [Claim 1] Process for producing heat and freshness in a flexible and elastic material characterized in that: * said material has 3 layers: 1 a layer provided with so-called cold compressible cells (2), 2 a layer provided with so-called hot cells that are less compressible than the previous ones (1), 3 an intermediate layer placed between the 2 previous layers and comprising nozzles (1), * and that said cells are in relief to allow easier mechanical compression and a return to the initial shape. * and that the 3 layers are assembled in a sealed manner so that each so-called cold cell (2) is in communication with a so-called hot cell (1) via one of the nozzles and that all the cells are filled with the surrounding gas during assembly, * and that the mechanical compression of said flexible material causes the compression and therefore the heating of the gas from the cells of the cold layer (2) which are compressible, towards the cells of the hot layer (1) which do not compress or only slightly , via the nozzles, * and that during mechanical decompression, the same gas which is found practically entirely in the hot cells (1) after compression relaxes and therefore cools via said nozzles towards the cells of the cold layer (2) which return to their shapes thanks to to the elasticity of said material, [Claim 2] Method for producing heat and freshness in a flexible and elastic material according to claim 1 characterized in that said material has airtight cells (1) and (2) containing a gas, the cells of which of the hot layer (1) intended to store the gas during mechanical compression of the material, are made more rigid thanks to a geometry of the cells and reinforcements adapted to be less compressible than those of the cold layer (2) intended to collect the same gas during decompression of the material. [Claim 3] Method for producing heat and freshness in a flexible and elastic material according to claims 1 to 2, characterized in that said material has airtight cells (1) and (2) containing a gas, of which the cells of the hot layer (1), intended to store the gas during mechanical compression of the material, are made more rigid thanks to a greater hardness of the material than those of the cold layer (2) in order to be less compressible as the cells of the cold layer (2) intended to collect the same gas during decompression of the material. [Claim 4] Method for producing heat and coolness in a flexible and elastic material according to claims 1 to 3, characterized in that said material comprises a hot layer (1) and a cold layer (2) having a thermal conductivity increased by the addition of powder with high thermal conductivity in said material and an intermediate layer (3) provided with nozzles having low conductivity. [Claim 5] Method for producing heat and freshness in a flexible and elastic material according to claims 1 to 4 characterized in that said material has airtight cells (1) and (2) containing air , CO2 or argon. [Claim 6] Method for producing heat and freshness in a flexible and elastic material according to claims 1 to 5 characterized in that said material has airtight cells (1) and (2) containing air , wet CO2 or argon. [Claim 7] Device for implementing the method according to claims 1 to 6, characterized in that the flexible and elastic material provided with sealed cells (1) and (2) containing a gas, has the shape of a sole which is placed inside the shoes, the cold layer (2) in contact with the foot and the warm layer (1) on the bottom side of the shoe in order to keep the feet cool despite a hot floor, or the warm layer (1 ) in contact with the foot and the cold layer (2) on the bottom side of the shoe in order to keep the feet warm despite a cold floor. [Claim 8] Device for implementing the method according to claims 1 to 6, characterized in that the flexible and elastic material provided with sealed cells (1) and (2) containing a gas, has the shape of a carpet which is placed on the ground in places of high traffic such as establishments open to the public or businesses so that the numerous pressures of the feet provide thermal or egul ati on. [Claim 9] Device for implementing the method according to claims 1 to 6, characterized in that the flexible and elastic material provided with sealed cells (1) and (2) containing a gas is arranged around a flexible pipe which allows, thanks to a peristaltic pump, to thermoregulate fluids during their transfers. [Claim 10] Device for implementing the method according to claims 1 to 6, characterized in that the flexible and elastic material provided with sealed cells (1) and (2) containing a gas is placed in a tire for a vehicle: the hot layer inside the tire to store said gas during mechanical compression of said material during movement of the vehicle and the cold layer at the periphery of the tire to expand the same gas during decompression of said material and thus cool the tire.